This invention relates to a bogie type landing gear and, more particularly, the invention is concerned with providing a soft landing gear suitable for short take-off and landing (STOL) aircraft wherein short aft mounted torque links operate to pitch the bogie downward causing the front tires to contact the ground first. The resultant landing force combines with tension forces in the torque links to act virtually up the strut, keeping piston bending and strut friction forces to a minimum.
In H. G. Conway's book "Landing Gear Design", page 120, FIG. 112(d), there is shown a bogie type landing gear somewhat similar to this invention. This type of prior art landing gear is suggested for aircraft with long strokes and high sink rates, such as STOL (short take-off and landing). The long stroke gears are normally subjected to increased piston bending and bearing friction during landing. Both of these undesirable conditions tend to obstruct vertical motion of the strut and to induce high vertical and drag loads into the aircraft. In the prior art landing gear (shown in FIG. 1), the tension load in the extension stop is in the same general direction as the resultant of the spin up and vertical loads acting on the aft axle. The drag components acting on the bogie and piston thus add to one another producing even higher piston bending and strut friction.
It would be most advantageous to provide a bogie type landing gear where the piston bending and strut friction forces could be held to a minimum. This could be accomplished by setting up the loading conditions so that the resultant piston force would be straight up the strut with little piston bending and friction. This would reduce the touchdown force required to overcome the extended air pressure and to initiate strut compression. Also, the couple forces on the strut bearings could be practically eliminated during the first portion of strut compression.